US2018156099A1PendingUtilityA1
Method of measuring an exhaust gas temperature
Assignee: GM GLOBAL TECH OPERATIONS LLCPriority: Dec 6, 2016Filed: Dec 6, 2016Published: Jun 7, 2018
Est. expiryDec 6, 2036(~10.4 yrs left)· nominal 20-yr term from priority
F01N 2610/03F01N 3/2066F01N 3/206F01N 2610/1453B01D 53/944F01N 2610/148F01N 11/005F01N 2610/02B01D 53/9431F01N 3/2033Y02T10/12F01N 2900/0406F01N 2900/1411B01D 53/9495F01N 2560/06F01N 2900/1404Y02T10/40B01D 53/9477
32
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Claims
Abstract
A method of measuring exhaust gas temperatures in an exhaust pipe of an internal combustion engine is disclosed. A value of a mass flow rate of exhaust gasses flowing into the exhaust pipe is determined. A signal yielded by a temperature sensor located in a first point of the exhaust pipe is sampled and applied as input to a first computational module that yields a corresponding first output signal. A value of the temperature of the exhaust gasses flowing in the first point of the exhaust pipe is calculated on the basis of a value of the first output signal.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A method of measuring exhaust gas temperatures in an exhaust pipe of an internal combustion engine comprising:
determining a value of a mass flow rate of exhaust gasses flowing into the exhaust pipe; sampling a signal yielded by a temperature sensor located in a first point of the exhaust pipe; applying the signal as input to a first computational module that yields a corresponding first output signal, wherein the first computational module has the following transfer function:
F *( s )=(1+τ RT ·s )· F ( s )
calculating a value of the temperature of the exhaust gasses flowing in the first point of the exhaust pipe on the basis of the first output signal; and wherein F(s) is the signal yielded by the temperature sensor, F*(s) is the first output signal and τ RT is a coefficient determined as a function of the measured value of the mass flow rate of exhaust gasses.
2 . The method according to claim 1 , wherein the first computational module implements the following equation:
f *( t )= f ( t )+τ RT ·f ′( t )
wherein f(t) is a value of the signal sampled at a time t, f*(t) is a value of the first output signal at the time t, and f′(t) is a value of a derivative of the signal at the time t.
3 . The method according to claim 2 , further comprising calculating the value f′(t) of the derivative of the signal with a finite difference equation.
4 . The method according to claim 3 , wherein the calculation of the value f′(t) of the derivative of the signal is performed with the following finite difference equation:
f
′
(
t
)
=
1
T
·
∑
k
=
0
n
C
k
·
f
(
t
-
kT
)
wherein T is a sampling period of the signal, f(t−kT) is a value of the signal sampled at the time t−kT, C k is a predetermined coefficient and n is a predetermined positive real number.
5 . The method according to claim 4 , wherein T is equal to 0.1 seconds, n is equal to 3, C 0 is equal to 11/6, C 1 is equal to 3, C 2 is equal to 3/2 and C 3 is equal to ⅓.
6 . The method according to claim 1 , further comprising:
applying the first output signal to a second computational module that yields a corresponding second output signal, wherein the second computational module has the following transfer function:
F
**
(
s
)
=
1
1
+
τ
TC
·
s
·
F
*
(
s
)
calculating the value of the temperature of the exhaust gasses flowing in the first point of the exhaust pipe on the basis of a value of the second output signal;
wherein F**(s) is the second output signal and τ TC is a coefficient determined as a function of the measured value of the mass flow rate of exhaust gasses,
7 . The method according to claim 6 , wherein the second computational module implements the following equation:
f
**
(
t
)
=
K
·
(
1
-
e
-
t
τ
TC
)
·
f
*
(
t
)
wherein f*(t) is a value of the first output signal at a time t, f**(t) is a value of the second output signal at the time t and K is a coefficient.
8 . The method according to claim 6 , wherein the second computational module implements the following equation:
f **( t )= f *( t )· K TC +f **( t−T )·(1− K TC )
wherein f*(t) is a value of the first output signal at a time t, f**(t) is a value of the second output signal at the time t, K TC is a coefficient determined as a function of the measured value of the flow rate of exhaust gasses, and T is a sampling period of the signal.
9 . The method according to claim 1 , further comprising estimating a value of a temperature of the exhaust gasses flowing in a second different point (P 2 ) of the exhaust pipe ( 275 ) on the basis of the calculated value of the temperature of the exhaust gasses in the first point (P 1 ).
10 . The method according to claim 9 , wherein the value of the temperature of the exhaust gasses flowing in the second point of the exhaust pipe is calculated with the following equation:
T
1
·
m
.
g
·
c
p
g
+
T
u
·
m
.
u
·
c
p
u
+
T
2
·
(
m
.
g
·
c
p
g
+
m
.
u
·
c
p
u
)
-
(
m
u
+
m
g
)
·
c
p
m
·
dT
m
dt
-
Q
.
mw
-
m
.
u
·
k
vap
=
0
wherein T 1 is a value of the temperature of the exhaust gasses flowing in a first point of the exhaust pipe, {dot over (m)} g is the value of a mass flow rate of exhaust gasses flowing in the exhaust pipe ( 278 ), c p g is a specific heat capacity of the exhaust gasses, T u is a temperature value of a fluid injected by an injector ( 279 ) located between the first and the second point of the exhaust pipe, {dot over (m)} u is a value of a mass flow rate of the injected fluid, c p u is a specific heat capacity of the injected fluid, T 2 is the value of the temperature of the exhaust gasses flowing in the second point of the exhaust pipe, m u is a value of a mass of the injected fluid in the exhaust pipe ( 278 ), m g is a value of a mass of exhaust gasses in the exhaust pipe ( 278 ), c p m is a specific heat capacity of a mixture of exhaust gasses and injected fluid in the exhaust pipe ( 278 ), T m is a mean value of the temperature of the mixture of exhaust gasses and injected fluid, {dot over (Q)} mw is a value of a thermal flux between the exhaust pipe ( 278 ) and the mixture of exhaust gasses and injected fluid, and k vap is a coefficient representative of an energy spent for mixing and vaporizing the injected fluid and k vap is a coefficient representative of an energy spent for mixing and vaporizing the injected fluid.
11 . A non-transitory computer readable medium comprising a computer program for measuring exhaust gas temperatures in an exhaust pipe of an internal combustion engine, the computer program having a program code, which when run on a computer, is configured to:
determine a value of a mass flow rate of exhaust gasses flowing into the exhaust pipe; sample a signal yielded by a temperature sensor located in a first point of the exhaust pipe; apply the signal as input to a first computational module that yields a corresponding first output signal, wherein the first computational module has the following transfer function:
F *( s )=(1+τ RT ·s )· F ( s )
calculate a value of the temperature of the exhaust gasses flowing in the first point (P 1 ) of the exhaust pipe ( 275 ) on the basis of a value of the first output signal; wherein F(s) is the signal yielded by the temperature sensor, F*(s) is the first output signal and τ RT is a coefficient determined as a function of the measured value of the mass flow rate of exhaust gasses.
12 . An internal combustion engine comprising an exhaust pipe having a temperature sensor located in a first point of the exhaust pipe and an electronic control unit configured to:
determine a value of a mass flow rate of exhaust gasses flowing into the exhaust pipe; sample a signal yielded by the temperature sensor; apply the signal as input to a first computational module that yields a corresponding first output signal, wherein the first computational module has the following transfer function:
F *( s )=(1+τ RT ·s )· F ( s )
calculate a value of the temperature of the exhaust gasses flowing in the first point (P 1 ) of the exhaust pipe ( 275 ) on the basis of a value of the first output signal; wherein F(s) is the signal yielded by the temperature sensor, F*(s) is the first output signal and τ RT is a coefficient determined as a function of the measured value of the mass flow rate of exhaust gasses.Join the waitlist — get patent alerts
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